In general, a detonation wave is generated in such a manner that a detonation gas is encapsulated in a tube, and ignited at a tube end to induce a transition from a deflagration wave to a detonation wave. The detonation wave thus generated is difficult to be applied to engineering, since it propagates at extremely high (hypersonic) speed of two to three km/sec with respect to a laboratory system (static system). A steady-state propagation of the detonation wave in static state with respect to a laboratory system (static system) is a requisite for an application of the detonation wave, but no such apparatus has been developed so far.
Meanwhile, in order to maintain a steady-state detonation wave in static state in an experimental apparatus, there are two issues to be cleared, as follows.
To begin with, the first issue is to develop a stabilizer to stabilize a detonation wave with respect to a hypersonic premixed gas flowing within an experimental apparatus. Until recently, conditions to stabilize a detonation wave were uncertain among the detonation researchers, and thus development of such a stabilizer was impossible.
The second issue is to generate a premixed gas itself which is both hypersonic and unburned. This is deemed as an extremely difficult issue. Because, in general, in order to generate a hypersonic flow, a method is taken in which an operating gas is brought to be high-temperature and high-pressure, and such an internal energy is converted to a kinetic energy through a nozzle. However, when an unburned premixed gas is accelerated in the same manner, combustion takes place at a stage where the operating gas (unburned premixed gas) is brought to be high-temperature, so that the hypersonic flow that is generated is already in a state of completely burned. To cope with this, a method is contemplated in which a gas fuel (combustible gas) and oxygen are separately brought to be high-temperature, accelerated to be hypersonic, and mixed together thereafter. However, in this method, although the gas fuel and oxygen do not begin to react upon the acceleration as they are separate in becoming high-temperature, the time period necessary for the subsequent mixture becomes longer than a characteristic time of flow, meaning that the mixture itself is difficult. Also, an expensive heating apparatus is required to make the operating gas high-temperature and high-pressure, which is another problem.
Accordingly, it is an object of the present invention to provide a steady-state detonation combustor and a steady-state detonation wave generating method which allow generation of a stabilized detonation wave by generating a premixed gas which is both hypersonic and unburned.